Incubation Station: A Reference Guide to Incubation Terms, Temperatures, Times and Humidity Levels

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In this incubation guide, I will take you through the common terms, temperatures, times, and humidity levels for common, assorted backyard poultry.

Often times, when people new to hatching are researching how to carry out the process, seasoned breeders will throw out terms that perhaps not everyone is familiar with. Hopefully this will act as a quick reference to de-mystify the process.

For the most part, the hatching process is the same for each bird species. In nature, the broody bird sits on her eggs and provides warmth and humidity. This steady contact begins the life process within the eggshell. With the help of an artificial incubator, humans can mimic the conditions that nature has instilled in birds, and quite easily at that.

Below is a list of terms commonly used in the incubation process.

Incubator – A device that mimics a broody bird by providing a controlled environment to keep eggs warm and at proper humidity levels for incubating to hatch day.

Turn Radius – This is used for incubators that rotate eggs with a rolling system. The turn radius refers to a relationship between circumference of the egg and the distance the egg is turned. This ensures that the mechanism flips the egg 180 degrees. The correct degree should be listed in your operator’s manual.

Turn Time Interval – The time between egg rotations. Most eggs should be turned at least 4 times per day but mechanical turning devices can be programmed to turn every 45 minutes to an hour. Check the operator’s manual for instructions.

Humidity – Humidity is the level of moisture inside the incubator. Most species need around 55-60% for most of the incubation time. In the last few days before hatching the humidity should be increased to 65-68%.

Hygrometer – Instrument used to measure the humidity in the air. Some incubators are equipped with these to ensure proper humidity levels during incubation. They can also be purchased separately.

Lockdown – Refers to the 2-3 days before hatch day where egg rotation stops and humidity levels go up. The incubator should not be opened during lockdown.

Candleing – The process of using a concentrated light source, like a flashlight beam in a dark room to shine through the eggshell and view the shadow of the progressing chick inside.

Pip – The first break of the eggshell that the chick makes when hatching.

Egg tooth- A hard appendage/nubbin on the upper tip of the chick’s beak to assist it in hatching. As the chick grows the egg tooth falls off, usually within the first week.

Hinge crack – In a normal hatch, the chick will create a hinge crack dissecting the egg in half around the equator of the egg. The egg is usually held together by a bit of membrane creating a hinge. The chick will push against the two halves of the hinge until it breaks through completely.

Membrane – It’s important for the membrane, which lines the eggshell, to stay humid during hatch. This rubbery film can begin to dry out and constrict the chick making it impossible to hatch.

Fluff out – After hatching the chicks should stay in the incubator until they fluff out. This means that all of their fethers have dried. Often, the incubator is too humid for this to occur. Chicks that won’t dry out can be moved to a brooder with a temperature of about 95 – 100 degrees.

Learn everything you need to know about incubating in my Incubation Series: